REFINE-bot: Furnace Cleaning Robot for Heat-transfer Efficiency Improvement

Abstract

In the oil and gas industry, scale accumulation on radiant coils within furnaces significantly reduces heat-transfer efficiency, leading to increased energy consumption. This paper introduces the REFINE-bot, a robotic system developed to improve the descaling process and operational efficiency in fired heaters. Unlike existing solutions which are mainly designed for specific tube sizes and positions and focused on inspection, the REFINE-bot integrates an adaptable clamping mechanism that adapts to both vertical and horizontal tubes of varying diameters (3"–8"), even in complex environments with narrow tube-to-tube and wall-to-tube gaps. An adaptive force control is also developed to online adjust the position of the cleaning relative to the tube surface to address uneven scale heights. We evaluated three different cleaning tools—a Knot End Brush, Wire Cup Brush, and Sandpaper—under simulated hard scale conditions in a lab environment. This evaluation revealed the cleaning tools’ limitations and helped to identify optimal safety parameters to prevent tube damage. The results showed that the 1-inch Wire Cup Brush, removing 431.1 μm of scale, achieved the highest descaling rate among the tested tools. The robot was successfully deployed in a real furnace setting to test its clamping and cleaning mechanisms on the actual scale. The real-world results demonstrated superior cleaning performance on the radiant coils of a furnace compared to traditional manual descaling methods, as evaluated by measured reductions in scale thickness and infrared thermal imaging. Furthermore, ultrasonic thickness measurements (UTM) were performed and indicated that there was no significant loss in wall thickness after the on-site experiments.